Aeronautical propeller



Jan. 26, 1932. s, REED 1,842,766

AERONAUTICAL PROPELLER Filed April 10, 1929 2 Sheets-Shet 1 ATTORNEY Jan. 26, 1932. s. A. REED I M AERONAUTICAL PRQPELLER 2 Sheets-Sheet 2 Filed April 10. 1929 A ORN EY I Patented Jan. 26,, 1932 UNITED STATES PATENT OFFICE...

' SYLVANUS ALBERT REED, or NEW YORK, N. Y; assIeNoR o THE REED PBOPELLER 00. me, or NEW YORK, 11. Y., A CORPORATION or NEW YORK AERONAUTICAL PROPELLER Application filed April 10,

My invention relates in general to aeronautical propellers and has reference more particularly to those having the type of blade described in U. S. Letters Patent Nos. 1,463,- 556, and 1,518,410, granted to me July 31, 1923, and Dec. 9, 1924, respectively, and the present invention is an improvement of the separate blade and adjustable pitch type set .forth in U. S. Patent No. 1,604,754 granted elongatedholes to permit pitch variation.

My present invention relates to means for increasing the stability and convenience of said adjustable blade attachment, and also relates to provisions for additional and improved means of pitch adjustment and hub construction; and further to the strengthening of the blade root-extensions in their mounting and preventing end and lateral displacement of the parts of the structure. Other important advantages possessed by my improvements will appear from the detailed description hereinafter given.

I have illustrated types of my improved variable pitch propeller in the accompanying drawings, wherein:

Figure 1 shows a plan view of a propeller constructed in accordance with my invention, looking in the direction of the axis of the drive-shaft, the outer portions of the blades being broken away and with the pivotpin bearing of the right-hand blade omitted. Figure 2 shows a perspective view of the rootportion of one blade with the prong conniact ing yoke and the pivot-pin bearing in ac Figure 3 shows a perspective view of the hub with its bearings for the yokes.

Figure 4 shows a perspective view of the prong connecting yoke or member.

Figure 5 shows on a reduced. scale-a side view of the propeller shown in the previous figures, with portions of the blades broken away.

Figure 6 shows a detailed view of the inner 1929. Serial No. 354,149.

end of the forked roots of the blades with their connecting and adjusting means, the prongs of one blade being shown in cross-section.

Figure 7 is a diagrammatic view illustrating the pitch change.

Figure 8 shows a similar view to Fig. 1, of a modified form of construction. Figure 9 shows a transverse sectional view of the structure shown in Fig. 8, with one of the root connecting yokes shown in full lines and the other shown in dotted lines.

Figure 10. shows a plan view of the inner portion of one blade with the huband the blade mounting.

Figure 11 shows a side View of the two blades with the hub and root connecting yokes.

Referring to Figures 1 to 7, inclusive, of the drawings, each blade and its adjuncts are constructed and arranged alike and are attached alike to the drive-shaft hub 1, which is common to both blades in the structure, so that a description of one blade and its adjuncts will serve for both, and the same reference numerals are used for the variousparts of each, but with a prime mark for the reference numerals of one of the blades and its adjuncts.

The blade 2, has its root portion forkedso as to provide a pair of extensions or prongs 3 and 4, with agap or interspace 5,disposed on the median line of the blade. The ends of the prongs are formed hooked shaped and are arranged so that their beaks 6 and 7, project inwardly towards each other, one above the other in overlapping relation with a horizontal space therebetween for the reception of a part'of the prong connecting yoke or member 8. This yoke is a substantial body and has preferably a central part or T 9, fitting between the overlapping hooks 6 and 7, of the blade and it is provided with a perforation 10, extendin through the yoke and T and coincident with the longitudinal axis of the blade, for the reception of the longitudiaal pivoting and stabilizing pin 11.

.The yoke 8, is arranged cross-wise of the overlapping hooks 6 and 7, and is formed with shoulders or abutments 12 and 13, disthe yoke, one above and the other below the central T 9, for engagement with corresponding parts or oflsets 14 and 15, on the beaks of the respective hooks 6 and 7, as indicated in Figs. 1 and 2. These interlocking parts are accurately fitted together so that the concave contacting parts of the inner face of the hooks conform to the convex parts of the yoke against which they lie. By means of this arrangement, the turning in one direction or the other of the blade on its longitudinal axis for Varying the pitch, and which of course is usually slight in its angular range of movement, serves to turn the yoke 8, on the pivoting and stabilizing pin 11, which thus serves as an arbor on which the yoke rocks.

The hub 1, is arranged within the embrace of the hooks 6 and 7, and is provided with an exterior upper and a lower lug 16 and 17, respectively, and at diagonally opposite places thereon, as will be understood particularly from F ig. 3. These lugs are slightly off-set and are flattened so as to provide a bearing surface of considerable extent or area for the fiat face of the yoke to shift and slide on when the blade is adjusted angularly.

The pivoting and stabilizing pin 11, which passes through the yoke and its T, has its inner end mounted firmly in a hole 18, in the side of the hub, and its outer end mounted in a bearing 19, fixed in the crotch of the fork prongs 3 and 4; see Figs. 1 and 2. This hearing or supporting member 19, by its location provides additional support and stabilit for the assembled parts.

The bearing device 19, is preferably made as a two part clamp 20 and 21, which extends over the faces of the blade and the parts are secured together by bolts 22 and 23. The part 20, extends down-through the crotch and meets the other part 21, at the surface level of the other face of the blade, and a hole 24, is provided between the two for the reception of the end of the pin 11. This provides transverse stability and a unit character of the assembly of the blade and hub. The pin 11, is provided with an external screw-thread 25, for the reception of a lock-nut 26, whichbinds against the end of the yoke-T 9, so as to further stiffen the assembly in such angular position of the blade as may have been given to it by operation of the adjusting means. The two art bearing 19, for the pin 11, gives a acility to assemblin the described parts, as they may be applier? after the pin is mounted in place in the yoke and hub, the length of the pin being accurately fitted so as to prevent any endwise play of the connected parts on the longitudinal axis of the blade.

When the blade is to be adjusted on its longitudinal axis to alter its pitch, by the ad justing means hereinafter descrlbed, the

parts stub-screws 27, are first loosened and after the adjustment, they are turned down hard so that their inner ends engage firmly the exterior of the hub 1. Each stub-screw is provided with an external screw-thread fitting into the threaded hole 28, extending through the blade prong, as shown in Fi 1, so that they'serve to hold securely the ad usted angle of the blade in respect to the axis of the hub. There are four of these stub-screws, one operating between each hook-shank and the adjacent side of the hub. See Figs. 1, 2 and 5.

The disposition of the blade hooks or extensions of corresponding edges of the two blades is that of inter-hooking, but the hub with the yokes on its opposite sides is interposed, and the hooks at such corresponding edges lie in a common plane which is normal to the axis of rotation.

The means, in addition to the stub-screws, for adjusting and fixing selectively the in tervals between the blade hooks or root extensions of the opposite blades, and thereby to change the angles of the blades to the plane of rotation, are arranged preferably between the shank of the hook of one blade and the beak of the hook of the other.

The said pitch adjusting means for the blades comprises a set of four eye-bolts like 29, operatively mounted between the hookshank 3, and the hook-beak 6, of the shank 3, and the yoke 8, engaging said hook-beak 6, and as the eye-bolts and their adjuncts are constructed and operate alike, the description of one will serve for the four.

The eye-bolt 29, has an eye 31, through which passes a securing-bolt 32, extending thence through hole 33, in hook-beak 6, of hook 3, and into a threaded socket 34, in yoke 8, the end of the bolt being threaded to fit the socket. The outer end of the eye-bolt 29, is threaded and such part passes tlIIOU h the hole 35, in shank 3, of the hook of the other blade. Lock-nuts 36, 37, are mounted upon the threaded part of bolt 29, one nut being disposed at each side of the hook-shank 3, so as to bind against the opposite sides of the shank when screwed down hard, as will be understood from Figs. 1 and 6. The inner faces of the lock-nuts are convex lenticular to always afford a bearing on a slew contact.

In order to alter the pitch of the blades, which is done simultaneously with both blades, the stub-screws 27 are first loosened and then either the lock-nuts on the inside or outside of the hook-shank is adjusted to its new position, and then the other lock-nuts are turned down hard to bind the shanks between each pair of lock-nuts, as will be understood more particularly from Fig. 6.

In Figure 7, I show a diagram explanatory of the relative adjustment movements of the two connected blades, in a certain angular relation with the plane of rotation. The

angular change is made around the pivoting and stabilizing pin 11, as a center, in cooperation with the yoke 8, and thus each change of blade pitch is produced by rotating each blade together with its yoke, as a unit around pin 11. The dotted line a-b, is normal to the edges of the hooks 6 and 7 shown in full line positions and a new angular adjustment is indicated by the dotted line rectangles representing the hooks of the associated blades, the line a-b changing to that indicated by a line cd, in the new angular relation. I may also provide a scale with index and figures to determine the desired angles of the blades to the plane of rotation, in order to facilitate the adjustment.

It will be noted that the pair of lugs on the hub for each blade are displaced to the extreme degree on the hub in the radial direction towards the opposite blade, so that the hooks may pass around and loop the body of the hub. The prongs of the fork are bowed outwardly from the hub with a relatively wide bend, so that the hook members have more strength than where a sharp bend is made therein. This is essentially the construction disclosed in my said Patent No. 1,604,757, but modified in detail.

In the modified construction shown in Figures 8 to 11 the radial stress-resisting lugs 16 and 17 are positioned somewhat differently from those in the other structure and stand out more from the outer sides of the,

hub 1. The rocking-yoke 8 which has angular movement on the pivoting pin 11, which has a bearing on the hub, is transposed to the exterior of the hooks 6 and 7*, of the root extensions or fork-prongs 3 and 4*, of the blade 2*. Filler blocks 40 and 40, are fitted Within the bends of the hook beaks and against the stress-resisting lugs. Each end of the yoke is secured by a bolt, indicated at 42 and 43, which pass through the hook and the filler block and the adjacent lug, and this serves to un te said parts firmly while in operation. The lugs are slotted at 44, 45, with the long dimension of the slot extending in the direction to permit angular adjustment of the blades on their longitudinal axes, substantially as set forth in my said patent. The filler blocks or pads have their faces which bear against the lugs, made flat to conform to the surface on the lug and to facilitateshifting the position of the blades in altering the pitch.

The expression an axis extending longitudinally of the propeller as used in the appended claims is intended to include not only an axis coinciding with the longitudinal axis of the propeller but also axes parallel thereto.-

I wish to be understood as not limiting my invention to the particular constructions and arrangements herein set forth, as it is manifest that various modifications may be made in the different parts thereof, without, howfork of a blade,

ever, departing from the spirit of the invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is: v

1. In a variable pitch aeronautical propeller, ahub, se arate blades each adjustable about its longitudinal axis to vary the pitch and each having root extensions receiving the radial thrust, each blade having a rocking-yoke connecting the root-extensions thereof, said yoke being operatively connectcd with said hub and the center of motion of the yoke being coincident with the longitudinal axis of its blade and the radial thrust received by said root-extensions being taken up by said hub.

2. In a variable pitch aeronautical propeller, a hub, separate blades each adjustable about its longitudinal axis to vary the pitch and each having root extensions receiving radial thrust, each blade having a rockingyoke connecting the root-extensions thereof, said yoke being operatively connected with said hub and the center of rocking movement of the yoke being coincident with the longitudinal axis of its blade, said yoke being so disposed as to receive the radial thrust of its blade and transmit the thrust to the hub.

3. In a variable pitch aeronautical propeller, a hub, separate blades each adjustable about its longitudinal axis to vary the pitch and each having root extensions receiving radial thrust, each blade having a rockingyoke secured between the root-extensions thereof and operatively connected with said hub, the center of rocking movement of the yoke being coincident with the longitudinal axis of its blade, said hub being provided with a bearing for said yoke and the yoke being interposedbetween said root-extensions and said bearing on the hub. v

4. In a variable pitch aeronautical propeller, a hub, separate blades each adjustable about its longitudinal axis to vary the pitch and each having root extensions receiving radial thrust, each blade having a rocking-yoke attached between the root-extensions thereof and operatively connected 7 with saidhub, the center of movement of said yoke being coincident with the longitudinal-axis of its blade, said yoke being so disposed as to engage said hub so that the radial thrust received by said root-extensions is transmitted to the hub through the medium of said yoke.

5. In an aeronautical variable pitch propeller,a hub provided with means sustaining the radial stresses of the blades when in operation, separate blades each adjustable about its longitudinal axis to vary the pitch, said blades each having its inner end forked and a rocking-yoke connecting the prongs of the said yoke and fork prongs betheir ing operatively connected with the stress-resisting means of said hub.

6. In a variable pitch aeronautical propeller, separate blades each adjustable about its longitudinal axis to vary the pitch, each blade being formed with forked roots having the fork-division on the median line of the blade, the ends of the fork-prongs being disposed toward each other, a hub arranged between the fork-prongs, an interposed yoke extending across said fork-division between said hub and the ends of the fork-prongs so as to be shifted on the hub in fixed relation with said prongs in response to the adjustment of the blade on its longitudinal axis, a pivotingpin disposed on the blades longitudinal axis and passing through said yoke with one end engaging said hub and the other engaging the crotch of the fork, the radial stresses of the blades being taken up by the hub through the medium of said yoke, and means for adjusting the blades on their longitudinal axis.

In a variable pitch aeronautical propeller, separate blades each adjustable about its longitudinal axis to vary the pitch, each blade being provided with forked roots having hooked prongs, a hub, the engaging roots of oppositely extending blades projecting beyond each other to the opposite side of the hub, a prong-connecting yoke secured to the prongs and interposed between adjacent prongs of a blade and the hub and capable of angular movement about the longitudinal axis of the blade as a center and in a plane normal thereto, means for maintaining the blades pivotally adjustable on their longitudinal axes, and adjustable connections between the roots of the blades for causing their adjustment on their longitudinal axes.

8. In a variable ler, separate blades each adjustable about its longitudinal axis to vary the pitch, each blade having forked roots with hooked prongs with beaks directed inwardly toward each other and disposed one above the other, a hub, the forked'roots of oppositely disposed blades extending past each other and embracing the hub, a yoke interposed between the hooked prongs of each blade and the adjacent side of the hub and shiftable on said hub on a center coincident with the longitudinal axis of the blade, the said hooked prongs engaging its yoke so as to shift the latter when the blade is angularly adjusted, pivotal connections between each blade and said hub on the median line of the blade, and adjustable connections between adjacent prongs of each'blade at the adjacent opposite blade-edge of the other blade for effecting the adjustment of the blades on their longitudinal axes.

9. In a variable pitch aeronautical propeller, separate blades each adjustable about its longitudinal axis to vary the pitch, each blade being formed with forked roots, the forkprongs being spaced apart edgewise, a hub,

pitch aeronautical propel-' a yoke provided with a lateral stem extending between said fork-prongs and said yoke being interposed between the hub and the forkprongs, a pivoting pin extending through said'yoke and having one end mounted on the side of the hub and the other in the crotch of the blade fork, means for adjusting the blades on their longitudinal axes and holding them in adjusted positions.

10. In a variable pitch aeronautical propeller, separate blades each adjustable about its longitudinal axis to vary its pitch, each blade being formed with forked roots with the ends of the fork prongs extending inwardly, a hub around which said fork prongs are disposed so that they lie to the far side thereof, adjusting bolts each secured to a fork-prong of one blade and 'adjustably connected with the adjacent opposite fork-prong of the other blade, whereby the bolts may be adjusted to vary the pitch of said blades.

11. In a variable pitch aeronautical propeller, a hub, separate blades each adjustable about its longitudinal axis to vary its pitch, each blade having forked roots with the prongs distorted and bent outwardly from each-other so that adjacent prongs are disposed upon opposite sides of the hub, said prongs having-the ends disposed upon the side of the hub, an adjustable connection prong at the corresponding edge of the associated blade for adjusting the blades on their longitudinal axes to alter the pitch, and means for holding the parts in adjusted posi tions.

12. For use with a propeller drive shaft, a propeller, equipped with blades and adj ustable as to pitch, and including a propeller hub havin an orifice for the reception of the propeller drive shaft and having flat faces on the sides of the hub opposite to the cooperating blades against which cooperating flat faces associated with said cooperating blades are adapted to bear to maintain the respective blades against centrifugal force, one of the faces of the hub having a substantially central depression, a pivot pin, arranged with its longitudinal axis coincident with the longitudinal axis of one ofthe blades, projecting into said depression, said pivot pin being effective to maintain the lon-' g'itudinal axis of said last named propeller blade constant while allowing adjustment of I sponding depressions in the hub and in the 'eral stresses by said blades for maintaining the alignment of the parts of the propeller.

14. lln a variable pitch aeronautical propeller, a hub, a blade adjustable about its longitudinal axis to vary its pitch, and a plurality of screws threaded through portions of said blade and adapted to bear upon but not passed through portions of said hub for maintaining said blade in any selected pitch angle.

15. In a variable pitch aeronautical propeller, a hub, a blade adjustable about its longitudinal axis relative to said hub to vary the pitch thereof, a screw threaded through one of said relatively adjustable parts and bearing against but not passing through a portion of the other relatively adjustable part for maintaining any selected pitch angle of said blade relative to the hub.

16. In an aeronautical propeller, a hub, a blade adjustable about an axis extending longitudinally of the propeller blade, said blade bearing against the hub for sustaining centrifugal stresses and being pivoted on opposite sides about which the blade is rotatable, whereby the blade is supported in position against lateral stresses by said pivots.

a hub, a

17. In an aeronautical propeller, blade including a blade portion and a root, said blade as a whole being adjustable about an axis extending longitudinally thereof and having a portion bearing against the hub for sustaining centrifugal stresses and being pivoted on opposite sides of the hub on coaxial pivots about which the root is rotatable, whereby the blade is supported in position against lateral stresses by said pivots.

18. In an aeronautical propeller; a hub; a blade having a length to width ratio of at least two to one, adjustable about an axis extending longitudinally of itself, having a portion bearing against the hub for sustaining centrifugal stresses, and being pivoted on opposite sides of the hub on coaxial pivots about which the blade is supported in position against lativots.

SYLVAN S ALBERT REED.

of the .hub on coaxial pivots the blade is rotatable, whereby 

